In the field of electronic devices, the trend toward decreasing feature sizes for miniaturization and increased device density continues unabated. According to the report by the U.S. National Science and Technology Council Committee on Technology, “Nanotechnology Research Directions: IWGN Workshop Report—Vision for Nanotechnology R&D in the Next Decade” (September 1999), systems built using devices in the dimensional domain of nanometers (called “nanoscale systems”) have the potential of increasing computer efficiency by millions of times. In this specification and the appended claims, the term “nanoscopic” will be used to characterize features in the dimensional range of less than about 1,000 nanometers. Those skilled in the art will recognize that many benefits of nanoscale devices are best realized when the minimum feature size dimensions are less than about 100 nanometers.
To achieve the benefits of nanoscale systems it would be especially useful to be able to make arrays of nanoscopic transistors. However, the problems involved in precise alignment of the elements of such nanoscopic devices have been difficult to solve. Individual nanoscopic field-effect transistors (FET's) have been made with photolithographically defined gates having fairly large dimensions. In other approaches, fabrication methods have been employed using free-floating nanowires and using flowing fluids to steer and coarsely align the nanowires to each other.
“Nanoimprint” lithography has been described by Stephen Y. Chou et al. in articles: “Imprint of Sub-25-nm Vias and Trenches in Polymers,” Applied Physics Letters, V. 67 (1995) pp. 3114-3116; “Imprint Lithography with 25 nm Resolution,” Science, V. 272 (Apr. 5, 1996) pp. 85-87; and “Nanoimprint Lithography,” J. Vac. Sci. Technol., B 14(6) (Nov./Dec. 1996) pp. 4129-4133. Various nanodevices have been made by using nanoimprint lithography methods, producing devices having a relatively large common third terminal (frequently the substrate) which is not nanoscopic. None of these prior solutions provides arrays of three-terminal fully-nanoscopic devices, based on only two nano-imprinted layers.